Why Ages That End In 9 Are The Most Meaningful

Are you celebrating year nine—19, 29, 39, 49, and so forth—soon? Now’s the perfect time to put yourself out there and make the most of your final year before you enter a new chapter in your life!

According to research published this week in Proceedings of the National Academy of Sciences, these are the years you are most likely to try something new, like getting a total head-to-toe makeover or going bungee jumping. Knowing that you’ll be entering unchartered territory—a new decade—your instinct is to search for something you've never experienced before.

Hal Hershfield, a psychologist at the University of California at Los Angeles and co-author of the study, explained to The Washington Postin an interview: “Years 30, 40, 50, they’re psychologically consequential. They seem big, they seem looming, and they seem more important to us than the others. They make us step back and think about how things have been going up until then and how we want them to go moving forward.”

He also adds that round numbers are salient in society, so they become strong motivators of behavior.

But the reserachers also found that people in their “nines” have the tendency to lean towards destructive behavior as well, like extramarital affairs or suicide.

“There’s a little bump at the nines,” explained Hershfield. “There are a lot of factors that go into these decisions. But the fact that we saw any bump was significant for us. When you’re talking about things like suicide, that’s a big deal. It might be numerically small but it’s practically significant.”